The present invention relates to a semiconductor device in which a metal bump is provided on an electrode pad connected electrically to a transistor, such as a liquid crystal driver, and to a method for fabricating the same.
A semiconductor device in which gold bumps or the like are provided on electrode pads, e.g., a liquid crystal driver uses a packaging technique such as a TCP (Tape Carrier Package) or COG (Chip On Glass), which is different from a ceramic/plastic package represented by CSP (Chip Size Package) or QFP (Quad Flat Package).
In an LSI product in which metal bumps are formed on electrode pads prior to shipment (hereinafter referred to as a product with metal bumps), it is essential to preliminarily form metal bumps before a probe test is performed thereon for the following reason.
FIG. 17 shows a probe test performed on a conventional product with metal bumps. In the conventional product with metal bumps, a plurality of electrode pads 92 connected electrically to a transistor (not shown) are formed on a substrate 91 provided with the transistor, as shown in FIG. 17. Gold bumps 93 are formed on the respective electrode pads 92 so that the probe test is performed by bringing the probe terminals 94 of a probe tester (not shown) into contact with the respective gold bumps 93. If a probe test is performed on the product with metal bumps shown in FIG. 17 before the formation of the gold bumps 93, the surface portions of the electrode pads 92 are damaged by the probe terminals 94 in contact therewith, as shown in, e.g., FIG. 18. If the gold bumps 93 are formed by plating growth on the electrode pads 92 after the probe test, a gold plated film grows abnormally to deform the gold bumps 93, as shown in FIG. 19, and thereby reduce the reliability. It is therefore necessary to perform a probe test on the product with metal bumps after the formation of the metal bumps.
However, the conventional product with metal bumps has the problem that a burn-in for quality assurance cannot be performed with respect thereto after dicing. Specifically, the problems are encountered that a product mounted on tapes such as a TCP is hard to handle during a burn-in performed with respect thereto and exhibits poor matching with a burn-in system since the tapes are mostly custom-made. If the conventional product with metal bumps is an unpackaged item such as a COG, it cannot be tested by a normal burn-in method. Thus, it is extremely difficult to perform a normal burn-in with respect to the conventional product with metal bumps.